concepts · updated 2026-05-13
Sunbender
confidence: high volatility: cold
The Sunbender® is Zomeworks' mirrored reflector and shade panel system for south-facing collectors and skylights. It directs additional winter sun into the building and provides summer shading — a
The Sunbender® is Zomeworks’ mirrored reflector and shade panel system for south-facing collectors and skylights. It directs additional winter sun into the building and provides summer shading — a single passive mechanism that improves both heating and cooling. It is listed alongside the DrumWall and Skylid as one of the defining features of the Baer House (1971).
What it does
In winter, a mirrored panel angled below a south-facing collector or skylight reflects additional sunlight into the aperture, increasing solar gain by more than 30% (per Sunspots Ch. 10: Ron Shore and Baer tests, February 1974). The reflector also acts as a windbreak, reducing convective losses from the glazing. In summer, the same panel pivots to shade the collector, blocking direct sun and preventing overheating.
No electricity. No motor. The same refrigerant-canister physics that actuates the Skylid can actuate the Sunbender’s position.
Patent history
The Sunbender developed through four patents:
| Patent | Year | Title | Key advance |
|---|---|---|---|
| US 3,884,414 | 1975 | Solar Heating Device | Skylid louver with interior/exterior refrigerant canisters — the underlying canister physics |
| US 4,275,712 | 1981 | Suntracking Device with Displaced Heating Surfaces | Tracker with heat-collecting plates separate from canisters; morning auto-reset |
| US 4,476,854 | 1984 | Gas Spring Solar Tracker | Gas spring for positive morning reorientation; large + small canister asymmetry |
| US 4,505,255 | 1985 | Summer/Winter Solar Control System | The shade louver system — overlapping louvers pivot between summer (shading) and winter (transparent) positions; solar-actuated by tracker |
Filed on the same day (November 14, 1983), US 4,476,854 and US 4,505,255 together define the complete Sunbender system: the tracker (4,476,854) orients the panel continuously throughout the day, while the louver control (4,505,255) provides seasonal mode switching between winter gain and summer shade.
The Baer House installation
The Baer House photographs show the Sunbender as the reflector/shade panels visible on the south elevation — large flat panels hinged or tracked below the south-facing drum wall glazing. The AIA slideshow (2009) labels the Baer Zome entry: “Drum wall, reflector/shades.”
From Sunspots (1975), Section 10.9:
Rough tests by Ron Shore and Baer, February 1974: a white or dull aluminum reflector of width equal to the skylight below it increases heat gain by more than 30% during hours the skylight faces the sun. The reflected light “gets in free” since glass area stays the same temperature.
The reflector in summer is lowered to shade the skylight. This is the Sunbender’s fundamental operating principle — the same physical panel serving both roles depending on angle.
Relationship to Skylid
The Skylid and Sunbender share the same refrigerant-canister physics but serve different functions:
| Feature | Skylid | Sunbender |
|---|---|---|
| Location | Below skylight interior | Outside, below collector |
| Function | Controls heat flow through skylight | Controls solar gain and shading of collector |
| Primary mode | Insulating louver (closes at night) | Reflector (winter) / shade (summer) |
| Tracking | East–west daily (seasonal) | Continuous solar tracking + seasonal |
The Sunbender is more sophisticated mechanically — it tracks the sun continuously throughout the day, not just sensing inside/outside temperature differential like the Skylid. The gas spring (US 4,476,854) provides the daily reset force.